First slide

Rate Measure

Question

If water is poured into an inverted hollow cone whose semi-vertical angle is 30° , then the its depth (measured along axis) increases at the
rate of 1cm/sec, the rate of which the volume of water increases when the depth is 24 cm.

Moderate

A

$19 π 19 π {cm}^{3} / \sec$
B

$92 π c m^{3} / \sec$
C

$192 π c m^{3} / \sec$
D

$200 π c m^{3} / \sec$

Solution

$\begin{array}{l} V = \frac{1}{3} π r^{2} h \\ \tan θ = \frac{r}{h} \\ V = \frac{π}{3} \times h^{2} \tan^{2} θ h \\ \frac{d v}{d t} = \frac{π}{3} \tan^{2} θ 3 h^{2} \frac{d h}{d t} \\ = π h^{2} \tan^{2} θ \frac{d h}{d t} \\ = π (24)^{2} \tan^{2} 30^{\circ} (1) {cm}^{3} / \sec \\ = π (24) (24) \times \frac{1}{3} \\ = 192 π {cm}^{3} / \sec \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App